Tuesday, November 9, 2010

Experimental Vs Survey method

Experimental Vs Survey method One common, but mistaken, belief is that the difference between surveys and experiments is a question of location, with surveys being conducted in the community and experiments in the laboratory. This is often the case, but not always. Experiments can be conducted outside laboratories, and surveys can be conducted in them. The main differences between experiments and surveys relate to the sorts of questions that each can answer. As we suggested earlier, experiments tend to be concerned with establishing causal relationships between variables, and they achieve this by randomly assigning participants to different treatment conditions. Surveys, on the other hand, tend to be concerned with measuring naturally occurring and enduring relationships between variables. Researchers who use surveys usually want to generalize from the sample data they obtain to a wider population. They do this by using the sample to estimate the characteristics of the population they are interested in. Why choose to carry out a survey rather than an experiment? Two reasons: sometimes we are only interested in observing relationships, and sometimes manipulations simply are not possible. This reasoning is not restricted to psychology. Astronomers or geologists rarely conduct experiments, simply because it is often impossible to manipulate the independent variables of interest (e.g. the position of certain stars or the gravitational force of a planet). Instead they rely largely on the same logic of controlled observation that underpins psychological surveys. But this does not mean that astronomy or geology are unscientific. Surveys can also allow researchers to eliminate some causal links. If there is no relationship (at least in the survey environment) between variables, this allows us to conclude that one does not cause the other. For example, if no relationship is found between age and intelligence, then it is impossible for intelligence to cause age, or vice versa (bearing in mind that a relationshipcould be concealed by a third, or background, variable).